Conventional power devices have upper and bottom electrodes respectively disposed on two surfaces of a chip. Due to the high power consumption of power chips, especially those applied in electric vehicles that consume thousands of watts, heat dissipation of the power chips has been a great challenge. Power modules used nowadays are still power devices with the structure having the upper and bottom electrodes. Such a structure requires wire-bonding and soldering to package the power module, which needs a more complicated process of fabrication and high costs for packaging equipment.